Indexable head diamond dressing tool

ABSTRACT

A diamond dressing tool including a tool holding head member and supporting shank having cooperating conical bearing surfaces urged together in tight frictional engagement by spring means operatively mounted therebetween. The head member is so mounted on the shank to permit its longitudinal movement along the shank bearing surface.

BACKGROUND OF THE INVENTION

This invention relates to indexable head diamond dressers and moreparticularly to an improved means for maintaining the concentricity ofthe mounted diamond with the axis of the shank portion of the cuttingtool. Indexable head diamond dressing tools are known in the prior artand are designed to equalize wear on the diamond cutting element. Seefor example U.S. Pat. Nos. 2,587,132; 2,761,441; 2,999,493; and3,452,735. Diamond cutting tools of this type have a tool holding memberrotatably cooperating with a supporting shaft. Resilient means urge thetwo members into tight frictional engagement. The tool holding membermay be rotated upon the application of a torque sufficient to overcomethe forces holding the tool holding member in its rotative position onthe shaft. The use of a rotatable tool holding member eliminates theneed for removing the shaft portion from its mounting when a freshcutting surface portion of the mounted diamond must be positioned foruse.

The prior art devices have not, however, eliminated the problem oflateral shifting of the tool holding member with respect to the shaftaxis. Previous designs rely on the accuracy and closeness of the fitbetween the rotating members. After a period of use, however, theconfronting surfaces will wear to a degree which will permit the toolholding member to shift radially with respect to the supporting shaftaxis with the result that the concentricity of the diamond point withthe shaft axis is no longer true. This is a particularly serious problemwhen, for example, tracer devices which allow no deviation frompredetermined datum dimensions are used. In such a device a diamondground to a specific conical point is mounted concentric with thesupporting shaft axis and is required to maintain its original datumpoint throughout repeated operations. Accurate concentricity of thismagnitude cannot be maintained merely by urging rotating memberconfrontation surfaces such as those disclosed in the prior art togetherwith resilient means. Wear will still result in loss of the diamondpoint's concentricity with the shaft axis.

SUMMARY OF THE INVENTION

Concentricity of the diamond point with the shaft axis can be maintainedover a prolonged period of use only by implementing a dynamic system inwhich the friction surfaces are permitted to move in wedging engagementupon wear, the movement being initiated by an optimally efficientapplication of friction surface engaging force, that is, force broughtto bear directly on a relatively concentrated surface area. Such adynamic system, as disclosed herein eliminates the problems associatedwith indexable head diamond cutting tools of the prior art.

In construction, the diamond dressing tool of the present inventionincludes a supporting shank which has a conical bearing surface having apredetermined angle with the axis of the shank. The invention furtherincludes a diamond cutting tool having a diamond with a cutting pointmounted concentrically at the forward end thereof. A head member mountedon the supporting shank has at one end a second conical bearing surfacecooperating with the shank bearing surface. At the opposite end is arecess for securely holding the diamond cutting tool which has side andbottom wall surfaces configured to be received therein. Spring means areoperatively disposed between the supporting shank and the head memberfor exerting engagement force in a direction parallel to the shank anddirectly against the conical bearing surfaces holding them in tightfrictional engagement. The head member is mounted on the shank so thatupon wear on the bearing surfaces, the spring means will initiatelongitudinal movement of the head bearing surface along the shankbearing surface. This compensates for the wear, thereby preventinglateral movement of the head member with respect to the shank axis andmaintaining the concentricity of the diamond therewith. In addition, asthe conical bearing engagement surface area is small, the engagementforce is concentrated over a limited area thereby insuring optimal useof the resilient force generated by the spring means.

Further, in accordance with the indexable head diamond dresser disclosedherein, the placement of the spring means proximal the conical bearingsurfaces also allows the length of the supporting shaft to be variedwithout effecting the rotational characteristics of the head member. Thedisclosed device is sturdy, simple to use and maintain, and may bemanufactured in a manner to permit the torque required to rotate thehead member to be preset at the factory.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view partially in cross section of the assembleddiamond dressing tool.

FIG. 2 is a side view partially in cross section of the partiallyassembled diamond dressing tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The diamond dressing tool 1 as shown in FIG. 1 includes a head member 2and a shank 3. The head member has an outer configuration consisting ofmultiple facets. This faceted configuration facilitates the rotation ofthe head with a tool member, not shown, having a complementary grippingsurface. The head, at one end, has a front recess 4 defined by recesswalls 5 for holding a diamond cutting tool 6. The diamond cutting tool 6consists of a slug 7 partially encasing a diamond 8 having a cuttingpoint 8' and a diamond slug carrier 9. When the diamond cutting tool 6is positioned in the recess 4 the diamond point 8' is concentric withthe head central axis. The cutting tool 6 is secured in the recess 4 byforce fitting in conjunction with a strong adhesive. The opposite rearend of the head member 2 is provided with an annular flange 10, having afront wall 11 and a rear wall 12 which forms a conical bearing surface12' having an angle with the head central axis of 30° ± 15'. The flangeforms a passage connecting the rear end of the head member to the bottomof the front recess 4.

The shank 3 has an elongated rearmost portion having a flat surface 13.The elongated portion is configured for non-rotatable mounting in aholder, not shown, with the flat surface 13 providing a contact pointfor a set screw. The shank has a conical medial portion forming aconical bearing surface 14. The conical bearing surfaces 12' and 14 alsoserve as friction confrontation surfaces. The shank conical frictionconfrontation surface 14 has an angle with the central shank axis ofapproximately 30° ± 15' and is configured to frictionally engage thehead member conical friction confrontation surface 12'.

The shank 3 is further provided with a tubular front extension defininga male fitting 15 which is concentric with the shank axis and comprisedof material distortable under predetermined force. A shank shoulder 16defines the rearmost extent of the shank bearing surface 14.

To assemble the indexable head diamond dresser, the tubular frontextension 15 of the supporting shank 3 is inserted through the headmember annular flange 10 until the respective conical bearing surfaces12' and 14 are in engagement, as shown in FIG. 2. In this position thehead central axis is coincident with the central shank axis. Springmeans, which in the preferred embodiment consists of two Bellevillewashers 17, and a flat washer 18, are next positioned around the tubularextension 15. The front end of the tubular extension is then subjectedto a predetermined rearwardly directed force from a device such as a120° punch inserted through the empty diamond cutting tool recess 4.This procedure forms the shank spring retaining means 19 whichcompresses the Belleville washers against the front wall 11 of the headmember annular flange 10. The spring means has a predetermined resilientforce directed parallel to the shank axis sufficient to urge the conicalbearing surfaces 12' and 14 into tight frictional engagement thuspreventing rotation of the head member 2 about the shank 3 absent theapplication of a predetermined torque.

As shown in FIG. 1 when the diamond cutting tool 6 is fitted into thehead member recess 4 a space 20 of predetermined size is defined by therear surface 21 of the tool carrier 9, the side wall surfaces 5 of thetool carrier recess and the front surface 22 of the shank springretaining means 19.

Prior to the need for replacement, wear on the diamond point 8' iscompensated for by rotating the head member by the application ofpredetermined torque, thus providing a new diamond cutting surface atthe point of operational contact. Any wear on the conical bearingsurfaces 12' and 14 which would result in lateral movement of the headmember is compensated for by the longitudinal movement of the headmember bearing surface 12' along the shank member bearing surface 14.This longitudinal movement is permitted by the above defined space 20and is initiated by the constant pressure exerted by the spring means17. The concentricity of the diamond point 8' with the shank axis ismaintained despite repeated rotative adjustment of the head member aboutthe shank by this dynamic cooperation of the spring means 17 with theconical bearing surfaces 12' and 14.

The above mentioned deforming force applied to the front end of theshank extension in forming the spring retention means 19 also presetsthe torque required to overcome the spring force holding the head member2 in its rotative cutting position on the shank 3. When the cutting tool6 is positioned within its recess 4, access to the shank springretention means as well as the spring means is prevented absent totalremoval of the cutting tool from its recess. This assembly insures thatthe operating characteristics which the dynamic system is designed topreserve will be controlled by the manufacturer. As already stated, thespring means 17 direct engaging force parallel to the shank axis ontothe bearing surfaces 12' and 14. Due to the positioning of the springmeans proximal the bearing surfaces the distance that the engaging forcemust travel is kept to a minimum thus insuring that maximum force willbe brought to bear on the surfaces 12' and 14.

As shown in FIGS. 1 and 2, the shank is provided with an axial bore 23extending its entire length. A tool may be inserted through the bore 23and placed in contact with the rear surface 21 of the tool carrier 9thus providing easy removal thereof when a replacement tool carrier mustbe inserted into the head member recess 4.

I claim:
 1. A diamond dressing tool comprising:(a) a supporting shankhaving a first conical bearing surface, said bearing surface having apredetermined angle with the longitudinal axis of said shank; (b) adiamond cutting tool having a diamond with a cutting point; (c) a headmember mounted on the supporting shank having,(1) a recess at the oneend thereof for securely holding the diamond cutting tool therein withthe cutting point of the diamond located on the longitudinal axis of theshank, and (2) a second conical bearing surface at the other endengaging with said shank bearing surface; (d) spring means operativelydisposed between the supporting shank and the head member for exerting aforce in a direction parallel to the longitudinal axis of the shank andagainst said conical bearing surfaces thereby holding them in tightfrictional engagement, (e) an inwardly directed annular flange at theother end of the head member forming a passage extending into the headmember from the other end, said flange including:(1) a rear conical wallsurface defining the second conical bearing surface, and (2) a frontwall surface facing the diamond cutting tool recess and surrounding saidpassage, (f) a male fitting on said shank extending forwardly of saidconical bearing surface, said fitting extending through said passagefrom the other end of the head member; and (g) a radially outwardlyextending spring retention means at the front end of said fitting, saidretention means being positioned in spaced facing relationship to thefront wall of said annular flange for compressively holding said springmeans therebetween to urge said conical surfaces togehter in tightfrictional engagement,wherein: (h) the passage is in communication withthe diamond tool recess; and (i) the male fitting extends into therecess thereby exposing the front end of the male fitting to theapplication of the deforming force prior to the placement of the diamondcutting tool in the recess,and wherein: (j) the diamond cutting tool inthe recess is axially spaced from the spring retention means.
 2. Thediamond dressing tool according to claim 1 wherein:(a) an axial boreextends through the shank and into communication with said recesswhereby pressure may be applied to the diamond cutting tool for removalthereof from the recess.
 3. A diamond dressing tool comprising:(a) ashank having:(1) an elongated rear portion configured to be detachablysecured in a holder, (2) a substantially conical medial portionconcentric with the longitudinal axis of said shank forming a firstconical friction confrontation surface, and (3) a generally tubularextension forward of the medial portion with a substantially radiallyoutwardly extending spring retention means at the end thereof; (b) adiamond cutting tool having a diamond with a cutting point; (c) a headmember mounted on the shank and having:(1) a recess at one end forsecurely holding the diamond cutting tool, and (2) an inwardly directedannular flange at the other end having:(i) a front wall facing therecess, (ii) a rear wall forming a second conical friction confrontationsurface, cooperating in frictional engagement with said first conicalfriction confrontation surface, and (iii) a passage formed by theannular flange extending into the head member with the head member beingso mounted on the shank that the tubular extension is positioned withinsaid passage and the spring retention means is in spaced facingrelationship to the front wall of the annular flange; and (d) springmeans positioned around the tubular extension and between the springretention means and the front wall of the flange for urging them apartand holding said first and second friction confrontation surfaces intight engagement.